This invention relates to new improvements in seat constructions which are used for mass transport vehicles such as busses, subway cars and other rail passenger cars and for public facilities and public houses such as railway stations and in public open space.
Seat constructions for mass transport vehicles are known in U.S. Pat. Nos. 3,873,155, 4,036,527, 3,797,887, and 2,720,914. In these patents, since the outer frame of the seat construction is integrally formed of one member, it is difficult to change the width of the seat construction which becomes necessary when changing the number of seats, changing the width of each seat or changing the installation method of the seat construction in a mass transport vehicle. Conventional seat construction such as the above require changes in the manufacturing line when various changes are performed as described above. Further, in conventional seat constructions, in order to form the outer frame, it is necessary to provide a large die. Preparing of the die is quite expensive. When the outer frame is formed by use of the die, such various changes as the above cannot be made without changing greatly the manufacturing line. In addition, the outer frame which covers all the outer surfaces of the inner frame merely serves as a cover, and does not constitute any particular structure in combination with the inner frame. Therefore, only the inner frame supports the load imposed on the seat construction, and thus must be strong. Further, since it also must support the outer frame, the total weight of the seat construction is, of necessity, heavy.
The present invention is derived from the above-mentioned circumstances, and therefore, an object of the present invention is to provide a seat construction which can increase the degrees of freedom in changing the number of seats, changing the width of each seat, and changing the method of installing the seat construction into a mass transport vehicle, and which is light but rigid, and further has a good appearance.
The above-mentioned object of the invention can be achieved by a seat construction comprising a composite inner/outer frame and at least two seat pans each having bottom and back portions secured to a composite inner/outer frame including:
an inner frame front horizontal straight cross member located at a position corresponding to front ends of the bottom portions of the seat pans, an inner frame back top horizontal straight cross member located at a position corresponding to the top ends of the back portions of the seat pans, and formed independently from the inner frame horizontal cross member; and an inner frame intermediate horizontal straight cross member located at a position corresponding to the juncture of the bottom portion and the back portion of each seat pan and formed independently from the inner frame front and intermediate horizontal cross members;
a first boomerang shaped inner frame side member formed independently from the inner frame horizontal straight cross members, enjoined to one end of each of the inner frame cross members;
a second boomerang shaped inner frame side member formed independently from the inner frame cross members and the first boomerang shaped inner frame side member, joined to the opposite end of each of the cross members; an intermediate frame member formed independently from the cross members and the side members joined to the cross members at substantially mid-way between their opposite ends:
the outer frame having a pair of outer frame boomerang-shaped side members formed independently from each other and secured to the first and second inner boomerang shaped side members; to encase peripheries of the side members, a front outer frame cross member formed independently from the paired outer frame boomerang shaped side members, encasing a periphery of the inner frame front horizontal straight cross member, and secured at its opposite ends to front ends of the outer frame side members; and a top outer frame cross member formed independently from the paired outer frame boomerang-shaped side members and the front outer frame cross member, covering a periphery of the inner frame back top horizontal straight cross member and secured at its opposite ends to top ends of the outer frame side member; an intermediate outer frame brace member formed independently from the paired outer frame boomerang-shaped side members and the front and top outer frame cross members, covering a periphery of the intermediate inner frame member, and secured to the intermediate inner frame member, whereby the outer frame members cooperate to provide a unitary composite inner/outer frame for supporting a load applied to the seat construction.
In the seat construction constructed as described above in accordance with this invention, the width of the seat construction can be freely changed by simply changing the length of each of a plurality of inner frame horizontal cross members and the length of each of the outer frame front and top cross members, so as to correspond to the change of the number of seats, the change of the width of the seat and the change of the method of installing the seat construction into the mass transport vehicle. Further, these straight and independently formed cross members are formed by cutting standard linear structural members existing in the market to a desired length, and thus the seat construction of this invention can be manufactured at low cost. Further, the inner and outer frame members cooperate to provide unitary composite inner/outer frame for supporting a load applied to the seat construction. Therefore, the construction of the invention is light yet rigid, and the outer frame members do not mar the appearance of the seat construction.
In the seat construction as described above in accordance with this invention, by fixing metal fixtures and/or support legs to desired positions on the seat construction by use of a desired method, the seat construction can be installed in a mass transport vehicle so as to face front and sideways, and can be installed in a desired posture in public houses such as railway stations and outside.
In the seat construction constructed as described above in accordance with the invention, by fixing the respective interconnecting portions of the above-mentioned members to each other by welding, the weight of the construction for each interconnecting portion can be decreased and the strength thereof can be increased.
In the seat construction constructed as described above in accordance with this invention, by including horizontal back straps whose number corresponds to the number of seat pans in the inner frame, the strength of the inner frame for supporting the seat pans is increased.
In the seat construction constructed as described above in accordance with this invention, by forming the members of the outer frame with stainless steel, the appearance of the seat construction is improved, and is substantially free from regular maintenance.
In the seat construction constructed as described above in accordance with this invention, by forming each of two side members of the inner frame with a plurality of channel shape sections connected to one another by welding, the strength of the two side members is increased without highly increasing their weight.
In the seat construction constructed as described above in accordance with this invention, by providing back covers, the strength of the seat construction can be increased and the appearance of their rear portions of the seat construction is improved.
By providing a concave portion in the back cover, the cover is straightened against bending or torsion applied thereto. Each of the inner frame boomerang-shaped side members is formed of three welded sections, each of which is channel-shaped. Thus the center portions of the boomerang-shaped side members, which are easily stressed, can be formed of materials which differ in thickness or quality from those of which the side portions of the boomerang-shaped side members are formed. Further, only the center portions can be formed in a pattern-draw molding process, and used as both the center portions of the right side members and the center portions of the left side members. In other words, since the center portions of the right side members and the center portions of the left side members have the same form they can be formed at a relatively low cost. The side portions are formed by bending which is performed at low cost.
By forming the intermediate horizontal cross member of the present invention as a straight tube, the seat construction is light, and highly torsion-resistant.
Further, if the opposite ends of the straight tubular members are welded to the outer surfaces of the first and second boomerang-shaped inner frame members after they pass through the corresponding boomerang-shaped inner frame members, the welded portions therebetween which are concentrically stressed, can be light yet tough.